Answer:
you need to add 300 mL of pure acid to the 300 mL of the 50% acid solution to produce a 75% acid solution.
Explanation:
Let x be the amount (in mL) of pure acid to be added.
The amount of acid in the 300 mL of 50% solution is 0.50 * 300 = 150 mL of pure acid.
When you add x mL of pure acid to this solution, the total volume of the mixture becomes 300 mL + x mL.
The equation for the amount of acid in the final mixture can be written as:
0.50 * 300 (acid from the original solution) + 1.00 * x (acid from the pure acid added) = 0.75 * (300 + x) (acid in the final 75% solution)
Now, let's solve for x:
150 + x = 0.75 * (300 + x)
150 + x = 225 + 0.75x
Now, subtract 0.75x from both sides:
0.25x = 225 - 150
0.25x = 75
Now, divide by 0.25 to isolate x:
x = 75 / 0.25
x = 300